EVIDENCE

Best evidence is current, up-to-date, relevant, valid, and grounded in research about the effects of a treatment, the potential for harm from exposure to particular agents, the accuracy of diagnostic tests, and the predictive power of prognostic factors (Cochrane, 1972). Although Archie Cochrane wrote this definition almost 50 years ago, it remains relevant to the practice of EBHC. Point-of-care clinicians and other decision makers need accurate, high-quality information to make important decisions.

Practice decisions require valid information about prevention, diagnosis, prognosis, treatment, and experience of care. The evidence available in any clinical decision-making can be arranged in an order of strength based on its likelihood of freedom from error. Many evidence pyramids have been proposed that rank the degree of bias by study design. As shown in a traditional hierarchy (Figure 1.2A), as one moves higher up the pyramid, the quality of the evidence is likely to improve. There are limitations to this hierarchical model, however.

The first limitation is that quality varies by study design and implementation approach. Consequently, there can be a blurring of quality differences across levels of the hierarchies in the pyramid. The use of Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) presented a framework where the quality of a study or the certainty of the evidence at the outcome level is judged for risk of bias specific to imprecision, inconsistency, indirectness, and publication bias (Brozek, 2009). To this end, the quality of the evidence can be rated up or down. Consequently, Murad et al. (2016) recommend a modified pyramid, shown in Figure 1.2B, where the straight lines are replaced with wavy lines to reflect the fact that the evidence at each level of the pyramid can be rated up or down based on domains of quality of evidence.

A second problem with the hierarchies shown in Figure 1.2A and B is the fact that SRs are at the top of the pyramid. Although SRs are the pillar on which EBHC rests (Munn et al., 2018), SRs may be a synthesis of any of the research designs on the pyramid, and consequently all would not be considered equal. Thus, Murad recommends, as shown in Figure 1.2C, that SRs not be at the top of the pyramid but be the lens through which the types of studies should be seen.

The results of SRs provide the most valid evidence base to inform clinical decision-making. The type of SR, that is, the lens through which one will examine their question, varies depending on the type of clinical question to be answered. Pearson et al. (2012) have long argued the need to gather evidence beyond that of effectiveness research as questions asked by decision-makers not only include effectiveness but also consider the feasibility, appropriateness, and meaningfulness of health practices and delivery methods. Answering these questions requires the use of a diverse range of research methodologies to generate appropriate evidence (Pearson, 2004). More information will be provided later in the chapter on the process of EBHC and searching for the best available evidence.

CLINICAL EXPERTISE

Best research evidence by itself is insufficient to direct practice. Clinical expertise, or the clinician’s accumulated experience, knowledge, and clinical skills, is also a necessary element of evidence-based decision-making. Clinical expertise incorporates two types of evidence—experiential and physical.

FIGURE 1.2

Evidence pyramid.

Source: Reprinted with permission from Murad, M. H., Asi, N., Alsawas, M., & Alahdab, F. (2016). New evidence pyramid. BMJ Evidence-Based Medicine, 21(4), 125–127.

Practitioners use their professional craft knowledge, the proficiency and judgment acquired through clinical experience, to determine whether best evidence applies to a particular patient or a group and whether the evidence should be integrated into the clinical decision. The aim is not to universally apply best evidence but to individualize the evidence based on practitioner assessment. This tacit, unspoken knowledge is used to assess the course and effects of implemented interventions. By using clinical skills and experience, the expert clinician rapidly identifies “each patient’s unique health state and diagnosis, their individual risks and benefits of potential interventions, and their personal circumstances and expectations” (Straus et al., 2000, p. 1).

An important piece of evidence integral to clinical expertise includes internal evidence generated from quality improvement data, patient assessment and patient perception data, and evaluation—what sometimes is called practice-based evidence. By measuring what we do and the outcomes for all patients, there is a rich source of evidence as to perceived and experienced effectiveness for different groups of patients and families. This type of knowledge guides the skilled practitioner in taking evidence and making decisions regarding the appropriateness for the individual patient.

Once new practices based on best evidence are implemented, the clinician assesses the course and effects of the intervention and uses their clinical acumen to make necessary adjustments (Shah & Chung, 2009). This dynamic balance between evidence and expertise is captured by Sackett and colleagues, as they describe the dangers in practice guided only by clinical expertise or only by best evidence: Without clinical expertise, practice risks becoming tyrannized by evidence, for even excellent external evidence may be inapplicable to or inappropriate for an individual patient. Without current best evidence, practice risks becoming rapidly out of date to the detriment of patients (Sackett et al., 1996). As this text focuses on the SR process, it will consequently emphasize best practice using empirical research; however, it is essential to recognize that the tacit knowledge of clinical expertise is a valuable component of EBHC.

PATIENT/FAMILY PREFERENCES AND VALUES

It is insufficient to simply blend expertise and evidence, for at the heart of EBHC is the patient with unique physical, emotional, psychological, environmental, and cultural perspectives. True EBHC requires the clinician to practice in a patient-centered model incorporating patient-specific evidence in decision-making and including the patient and family as co-decision makers in the selection of interventions or approaches for the patient’s improved health. Failure to consider these patient preferences and practicing from a medical model leads to unintentional bias toward a professional’s view of the world. Recognizing that there may be a monocultural bias in evidence, healthcare providers must be prepared to make “real-time” adjustments to their approach to care based on patient and family perspectives.

Making the patient central to the decision-making process involves the following:

Shared decision-making begins with finding out what matters to the patient. Being aware of ethnocultural beliefs and traditions of patient populations enhances the clinician’s openness to individual and family perspectives. With mutual understanding and respect, both the professional’s perspective as a healthcare provider and the patient’s preferences can be weighed together in arriving at the treatment plan for the individual patient. In shared decision-making, there is a bidirectional, respectful, collaborative relationship where the clinician contributes technical expertise (evidence and clinical expertise) while the patient is the expert on their own needs, situations, and preferences (Truglio-Londigran & Slyer, 2018). Bringing the two together advances the goal of the decision-making process to match care with patient preferences and to shift the locus of decision-making from solely the clinician to be inclusive of the patient (Johnson et al., 2010), which is more likely to result in care that is meaningful and valuable to the patient.

Bastemeijer et al.’s (2017) qualitative SR examined what patients say they value in healthcare; their results are presented as a taxonomy that can guide the patient–professional interaction. Figure 1.3 illustrates the seven interrelated themes that fall within the patient–professional interaction. The authors suggest that there is a relevance to the sequence of these elements. Recognition by professionals of the patient’s uniqueness and autonomy leads to the professional behaving with compassion, professionalism, and responsiveness, thereby creating interaction based on partnership and empowerment. Table 1.1 provides a description of each of the seven elements.

Attending to the patient perspective goes beyond clinical practice and is a priority in clinical research as well. Including the perspectives of the patient as an end user of the research enhances the relevance of research to actual health and perhaps will even decrease the evidence–practice gap. The Patient-Centered Outcomes Research Institute (PCORI) is mandated to improve the quality and relevance of evidence available to help patients, caregivers, clinicians, employers, insurers, and policy makers to make informed health decisions (www.pcori.org). To meet this mandate, PCORI involves patients, caregivers, clinicians, and other healthcare stakeholders, including payers and researchers, throughout the process.

FIGURE 1.3

Taxonomy of patient values and preferences.

Source: Reprinted with permission from Bastemeijer, C. M., Voogt, L., van Ewiik, J. P., & Hazelet, J. A. (2017). What do patient values and preferences mean? A taxonomy based on a systematic review of qualitative papers. Patient Education and Counseling, 100(5), 871–881.

CLINICAL CONTEXT

Context is any circumstance in which something happens. Contextual evidence is based on local factors that are specific to a community or setting and helps determine the feasibility of a specific intervention or approach. Clinical care takes place within many differing contexts; those contexts dictate the nature of that care and the evidence available to assist in decision-making (Dieppe et al., 2002). Sources of evidence in the clinical context may include the following:

These sources of data can be used to guide practice decisions and practice changes and inform about the need for research-based evidence. Adapting evidence-based practices to the local context requires comparing the pieces of evidence for similarities or differences in context and determining if these differences or similarities matter and ultimately adapting the intervention to be more congruent with the local context. To guide clinicians in adapting high-quality evidence and CPGs to accommodate the local context, the ADAPTE framework and toolkit, available through Guidelines International Network (GIN), can serve as a guide. This framework is discussed further in Chapter 12.

ASK

There is both an art and a science to asking clinical questions to efficiently obtain needed information to make informed clinical decisions about patients. Information needs from practice are converted into focused, structured, and searchable questions that are relevant to the clinical issue by using the PICO (population, intervention, comparison, outcome) mnemonic or similar approaches. PICO provides a systematic way to identify the components of the clinical issue and structures the question in a way that will guide the search for evidence (Stillwell et al., 2010). These four components of a good clinical question can be thought of as data fields that will aid in the search for evidence and answers. How the question is framed or whether the question will include all components of PICO, such as a “C” or comparison, will depend on the type of question. One of the benefits of developing a thoughtful and careful question is that it makes the search for evidence easier and more efficient. A focused clinical question provides the keywords and phrases needed for searching to be readily apparent.

ACQUIRE

After the question is framed, the next step in the process is to acquire the evidence. Practitioners should first search sites where research has already been critically reviewed and summarized and deemed of sufficient quality to guide clinical practice. These resources are called filtered resources. The 6 “S” model (updated over time from the 4 “S” and 5 “S” model with the growth of evidence summary services) describes six layers of evidence sources when searching for an answer to a clinical question (DiCenso et al., 2009). Using this top-down approach to obtaining the best evidence most efficiently, searching should begin at the highest level on the pyramid recognizing that high-level evidence resources may not be available for all questions. Figure 1.5 illustrates the 6 “S” model.

The highest level of filtered resources features evidence-based clinical evidence integrated into computerized decision support systems built into the electronic health record (EHR). Although not a reality yet in most EHRs, this would allow patient data to be matched with evidence to generate patient-specific recommendations.

Summaries are the next level to draw from. This source of evidence includes Clinical Practice Guidelines (CPGs) that draw evidence from SRs as well as electronic evidence-based textbooks. Clinical guidelines are generally developed by professional groups (with representation from government agencies and specialty practice organizations) through a rigorous process of gathering, appraising, and combining evidence of varying levels. Guidelines provide actionable recommendations (with grading of the evidence) that inform practice decisions. Examples of sources for evidence-based clinical guidelines include the Agency for Healthcare Research and Quality (2004) (AHRQ), the U.S. Preventive Services Task Force (USPTF) recommendations, GIN, Emergency Care Research Institute (ECRI) Guidelines Trust, the Registered Nurses Association of Ontario (RNAO), the American Cancer Society, the World Health Organization, and the Oncology Nursing Society. Electronic textbooks such as Dynamed, UpToDate, EBSCOhost, and Natural Medicine provide a body of evidence at a topic level. Topic-level summaries, drawn from SRs if possible, provide a full range of evidence concerning management options for a given topic or health problem (e.g., congestive heart failure). Summaries are kept up to date and provide a mechanism for passive decision support by linking them to individual patient problems.

FIGURE 1.5

The 6 “S” levels of organization of evidence from healthcare research.

Synopses of syntheses provide a summary and critical appraisal of SRs and usually a discussion regarding the strength of the evidence and the clinical applicability of its findings. As such, the clinician can more confidently examine whether it is applicable to their question and population of interest. Many synopses also provide additional discussion on the practice implications of the study and a rating of the evidence. Synopses of SRs can be found in evidence-based journals such as Evidence-Based Nursing, BMJ Evidence-Based Medicine, and the ACP Journal Club.

Syntheses are SRs where the authors have synthesized research on a defined clinical question. As SRs use a rigorous approach to comprehensively search and appraise studies and provide a summary of the pooled findings, syntheses provide a valuable level of evidence for informing clinical decision-making and are considered more valid than a single study. The search for SRs should initially concentrate on sites that focus on this type of evidence. These include the following:

The clinician must, however, critically appraise the SR for its rigor and relevance.

Synopses of a single study provide limited information specific to one study but it has been reviewed by an expert with output consisting of an overview and appraisal of the study. The general standard is that a practice change should not be based on a single study but requires higher-level evidence sources such as SRs or synopses of these reviews. Sources of synopses of studies include evidence-based journals such as Evidence-Based Nursing and BMJ Evidence-Based Medicine.

The base of the pyramid of evidence resources draws from unfiltered resources—originally published single studies which are searched for from common databases such as PubMed and CINAHL. In searching, the components of the PICO question can be used as search terms. One can further limit the search by stipulating the preferred research design for the question being asked. Knowing the preferred research design (the strongest evidence), one can begin the search by stipulating the research approach, thus narrowing to the “best” available evidence. The reader needs to critically appraise the article in order to determine the balance of its strengths and weaknesses.

APPRAISE

All evidence needs some form of appraisal. If the evidence has been pre-appraised, it still needs to be examined for

Chapa et al. (2013) provide a decision guide to appraising and using pre-appraised evidence.

If the retrieved evidence has not been from a synopsis (whether of an SR or individual study), then it is important to appraise the retrieved studies for quality and confidence in the trustworthiness of the data and their clinical usefulness. The appraisal process differs depending on whether it involves primary (individual study) or secondary research (systematic review) and the type of research design used. An SR by Katrak et al. (2004) examined 127 critical appraisal tools and concluded that there was no gold-standard tool for a specific design and no generic tool that can be used across study types. More recently, Aromataris and Munn (2017) emphasized the importance of using a validated critical appraisal tool yet acknowledged that there is no gold-standard tool. A discussion of the most commonly used, validated, and reliable tools is found in Chapter 8, “Choosing the Right Critical Appraisal Tool.”

APPLY

After high-quality evidence/studies have been selected from the appraisal process, the next step is to determine whether there is applicability to one’s own context and patient population. The decision to apply results in real-time clinical practice is based on the magnitude of the findings, their applicability to different populations, and the strength of the evidence.

In considering the magnitude of the findings or the clinical significance, the practitioner must ask, “Is the size of the benefit (effect size) likely to help my patient?” This requires agreement between the patient and the practitioner on the outcome that is important to the patient. The practitioner can provide the evidence to the patient as to the likelihood of benefit or harm that is specific to the intervention, comparison interventions, and the desired outcome in plain language so that the patient can make an informed decision.

In research that examines whether interventions work or not, such as randomized controlled trials (RCTs), the intervention is often tested in a carefully defined population under tightly controlled situations that do not simulate real-world settings. The practitioner must determine whether the settings and patient populations from the evidence-based studies are sufficiently similar to those from their own routine practice and whether the interventions used can be duplicated and are acceptable to their patients. Thus, in the application stage, one is questioning the applicability of the findings to one’s own context and one’s own patient population. It is important to recognize that although the data may be objective, the meanings have intrinsically subjective values that are dependent on the audience and may differ among nurses, physicians, patients, and administrators (Manchikanti et al., 2007).

A final factor to consider in examining applicability is the strength of the evidence. It is not unusual for studies to be of poor quality, and frequently the recommendations of SRs emphasize the need for more high-quality trials. One can consider the progression of recommendations for bed rest in the presence of low-back pain to illustrate this. Recommendations from “experience” called for bed rest in episodes of acute back pain and sciatica. Early recommendations from lower levels and lower quality of evidence found bed rest to be effective in alleviating low-back pain. Subsequent higher-quality clinical trials found different results. In a 2010 SR on whether to advise patients to rest in bed versus stay active for acute low-back pain and sciatica, moderate-quality evidence showed that patients with acute low-back pain may experience small benefits in pain relief and functional improvement when advised to stay active as compared with recommendations for bed rest. There was little or no difference between the two approaches in patients with sciatica (Dahm et al., 2010). In other words, activity was recommended. However, it must be pointed out that the hierarchy of evidence is not absolute. It may be that observational studies with sufficiently large and consistent treatment effects are more compelling than small RCTs (Manchikanti et al., 2007).

ACT AND ASSESS

If the practitioner identifies that the evidence can be applied to practice, the final steps are to act (put it into practice) and to assess whether the expected outcomes are achieved. This ongoing monitoring and review provide ongoing practice-based data on efficacy and effectiveness.